All my dash lights will come on but car will not turn over

Asked by GuruHJ8DN Aug 14, 2019 at 01:09 PM about the 1998 Volkswagen Passat 4 Dr GLS 1.8T Turbo Sedan

Question type: General

Tried starting my car and it would not turn over
ignition like me coming on and still would not turn
over try to compression start my car and that field
also another lost right now so any help would be
very appreciated thanks

1 Answer

4,310

Just so many giving poor advise related to driving a vehicle on a dead battery or undercharged one for that matter. Pulling a stored OBD code will tell you nothing related to a battery and an ongoing battery draw. First of all one must understand how a voltage regulator works within an alternator. The alternator is designed to work with a good charged battery not a poorly charged one that has been jumped from another vehicle, Leaving the downer vehicle battery connected after cranking up the dead battery for ten minutes does very little to protect the alternator of the vehicle with the dead battery. It takes about 7 miles of travel in a vehicle to charge the battery from what it discharged to crank the vehicle at 2500 RPM. Moreover as the alternator is designed to put out between 13 to 14.5 amps to recharge and maintain a good charged battery without burning up the internal voltage regulator an electrical draw or short in the system will increase the amps needed as will the poorly charged battery. Its like running the vehicle on the alternator only that will surely burn up the voltage regulator in a very short time. Some alternators are 60 amp and some are 100 amp but neither is designed to put out that amount of amperage continues for any extended length of time. The best procedure is to remove the battery from the vehicle and charge it if it is determined by a load test to be a good battery with no bad cells. Once it is charged and installed a draw test should be done to see if there is a battery draw draining the battery when the vehicle is not in use. The alternator should also be removed and tested even though a field test can be done without test equipment after the battery is charged and reconnected. Prior to a draw test the vehicle if it will crank up should be started and the positive cable removed from the positive post for a second to see if the vehicle dies. If it is a bad alternator the engine will die immediately once the positive currant is disconnected. If it doesn't stop running the positive cable should be reconnected at once as disconnected is the same as running a vehicle on a dead battery and will burn up the internal voltage regulator.If the engine continues to run on the alternator alone the alternator is good and putting out plenty of amperage. Doing a draw test is a good idea if the cause of the dead battery is unknown such as leaving on headlights that have drawn down the battery. This is a test that can be done with a voltage meter or a simple 12 volt test light. To do this test with a test light all that is needed is to remove the negative cable from the negative post and connect it inline. This is done by connecting one end of the test light to the negative post of the battery and the other probe end of the test light to the negative cable removed. If any draw is present the test light will be lit. Next is to remove all fuses that would normally draw a battery when a vehicle is not in use such as the dome light fuse, radio fuse , cigarette liter fuse and such. After all these fuses are removed the light should not be lit. If so there is no draw to be concerned with. however if the light still remains a circuit is drawing on the battery and should be located and checked for a short. To do this is relatively easy. Just remove one fuse at a time checking to see if the test light goes out. If it doesn't replace that fuse and move to the next until the one fuse that effects the test light is located. Assuming one fuse does effect the test light and the light goes out once the fuse is removed then that would be the circuit casing the draw on the battery and should be checked for problems related to an electrical short. For instance lets say its the brake light fuse causing the draw. The next step would be to visually check all the brake light bulbs and sockets for corrosion or broken bulbs as well as frayed wiring of a positive nature touching the body of the car. You might find a shorted wire where the brake light actuator is mounted on the brake pedal . Perhaps a burned wire connection could be found. Use sound judgment when it comes to electrical to prevent further damage.

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